1. Field of the Invention
The present invention relates generally to probe card devices, and more particularly, to a probe card device which can test a plurality of semiconductor devices as they are formed on a wafer.
2. Description of the Background Art
Semiconductor devices are operated with higher power supply voltage than the normal level in use or in a more severe peripheral temperature condition than the normal temperature condition or maintained in a higher temperature condition for testing before shipment, so that devices with the possibility of causing initial failures could be removed. The test conducted for the purpose of improving the reliability of the semiconductor devices is called xe2x80x9cburn-inxe2x80x9d.
A conventional burn-in device for a burn-in test will be now described. The burn-in devices are divided into those for a burn-in test a semiconductor device formed in a wafer and those for testing of such semiconductor devices formed in a wafer in an assembled arrangement.
Herein, the former burn-in device will be described. Referring to FIG. 17, a wafer under test 101 having a semiconductor device formed thereon is placed at a wafer prober 105. A burn-in board 102 is provided opposing to wafer under test 101. Burn-in board 102 is electrically connected to a test head 106 and a tester 108 through a signal cable 107.
Referring to FIG. 18, burn-in board 102 is provided with a plurality of board needles 103 respectively to be connected with a plurality of electrodes (pads) formed in the semiconductor device and a board connect pin 104 electrically connected to the test head 106.
Referring to FIG. 19, in order to improve the processing performance in a burn-in test, a burn-in board 102 having a plurality of sets of board needles series 103 corresponding to individual semiconductor devices is used. The conventional burn-in device has the construction as described above.
The conventional burn-in unit suffers from the following problems. Burn-in board 102 is formed of glass epoxy resin or polyimide resin or the like, while wafer under test 101 is typically formed of silicon, and the materials of these elements have different thermal expansion coefficients.
As a result, if the temperature is raised in a burn-in test, the difference in the thermal expansion coefficients of the materials of burn-in board 102 and wafer under test 101 sometimes causes board needle 103 to shift from a prescribed pad in the semiconductor device in the surface of wafer under test 101.
The difference in the warps of burn-in board 102 and wafer under test 101 sometimes causes board needle 103 to be detached from the pad in the semiconductor device, and a burn-in test cannot be successfully carried out.
The present invention is directed to a solution to the above-described problems, and it is one object of the present invention to provide a probe card device which can surely touch a prescribed electrode in a semiconductor device formed in a semiconductor substrate under test and successfully carry out a burn-in test.
The probe card device according to the present invention for testing a plurality of semiconductor devices formed on a substrate under test includes a probe substrate opposing the substrate under test and having a plurality of probe electrodes in electrical contact with the semiconductor devices and formed of the same material as that of the substrate under test. The probe substrate has a first seal member and a substrate through hole. The first seal member is provided on one surface opposing the substrate under test to hold the substrate under test by vacuum and seal between the substrate under test and the probe substrate. The substrate through hole is formed through the probe substrate for evacuation.
Thus, the probe substrate formed of the same material as that of the substrate under test has the same expansion coefficient as that of the substrate under test. As a result, if the temperature is raised in a test, a plurality of probe electrodes formed in the probe substrate and prescribed electrodes in the semiconductor device formed on the substrate under test corresponding to the probe electrodes will not be relatively shifted from one another. As a result, the probe electrodes and the prescribed electrodes surely come into contact, so that the semiconductor device may be surely tested.
A film is preferably provided at the other surface of the probe substrate to match the warps of the probe substrate and the substrate under test in testing.
In this case, the spacing between the probe substrate and the substrate under test will be substantially constant within the surface of the substrate under test. As a result, the plurality of probe electrodes formed in the probe substrate and the electrodes of the semiconductor device will not be departed from one another, so that they come into contact even more surely.
A plurality of patterns segmented by dicing lines are formed on the one surface of the probe substrate and the substrate through hole is formed in the region of the dicing lines.
In this case, the substrate under test is held by vacuum, and therefore the streaming resistance at the time of exhausting the space between the probe substrate and the substrate under test is relaxed, so that even evacuation may be efficiently achieved. As a result, the substrate under test can be evenly adsorbed.
The size of one shot pattern is preferably different from the size of one shot for the semiconductor device formed in the substrate under test.
In this case, the probe electrodes in the probe substrate can be surely brought into contact with prescribed electrodes in the semiconductor device formed in the substrate under test. More specifically, if the substrate under test is curved to form convex toward the side opposing the side of the probe substrate, the size of one shot pattern may be set smaller than that of the semiconductor device, so that the electrodes in the substrates can be surely brought into contact. Meanwhile, if the substrate under test is curved to form convex toward the side of the probe substrate, the size of one shot pattern may be set larger than that of the semiconductor device, so that the electrodes can be surely brought into contact.
The pattern of the probe substrate preferably has at least two interconnection layers.
In this case, the flexibility of the pattern formed in the probe substrate is improved. Sufficient current may be stably supplied for testing the semiconductor device.
The pattern of the probe substrate includes a prescribed circuit portion pattern for use in testing the substrate under test. The prescribed circuit portion pattern includes a power supply generating circuit, a clock signal generating circuit, a test circuit or a counter circuit.
Thus, defects in a particular part of the semiconductor device may be found early and the semiconductor device may be operated at a high speed. Thus, semiconductor devices with the possibility of causing initial failures may be removed in earlier stages. Data on the failure percentage or defective positions may be collected to alleviate the quality control of the semiconductor devices.
The probe electrode formed in the probe substrate preferably includes a bump electrode.
Thus, damages to prescribed electrodes in a semiconductor device formed in the substrate under test may be restrained. As a result, if a pad electrode to be wire-bonded is applied as a prescribed electrode in a semiconductor device, failures in wire-bonding to the pad electrode may be reduced.
The first seal member formed in the probe substrate preferably includes a ring-shaped insulating film formed around the outer periphery of the probe substrate.
Thus, the ring-shaped insulating film comes into contact with the vicinity of the outer periphery of the substrate under test, and the substrate under test may be surely adsorbed by vacuum.
The probe substrate preferably has at least two substrate side alignment marks on the side of the probe substrate corresponding to alignment marks formed in the semiconductor device for alignment with the substrate under test.
Thus, when the substrate under test is held by vacuum, the probe substrate may be readily positioned with respect to the substrate under test.
The size of the substrate side alignment marks is preferably different from the size of the alignment marks formed in the semiconductor device, and alignment marks larger among those formed on the side of the substrate and semiconductor device are formed of a material which reflects infrared radiation and the smaller marks are formed of a material opaque or semitransparent to infrared radiation.
Thus, an infrared beam is used for scanning, and a beam reflected from the larger size alignment marks is measured. Then, based on the position at which this reflected beam is shielded by the smaller size alignment marks, the positioning of the probe substrate relative to the substrate under test can be readily achieved.
An insulator board opposing the other surface of the probe substrate is preferably provided. At least one of the insulator board and the opposing surface of the probe substrate is provided with a second seal member to seal between the probe board and the insulator board in order to held the probe substrate and substrate under test by vacuum, and the insulator board has a board through hole to evacuate the substrate under test through the substrate through hole.
Thus, the probe substrate is placed between the insulator board and the substrate under test for testing. At this time, a cable connected to a tester necessary for testing can be connected to the insulator board without being directly connected to the probe board, and therefore the probe can be more readily handled.
A groove is preferably formed at the surface of the insulator board surrounded by the second seal member.
Thus, the substrate under test is adsorbed by vacuum through the probe substrate, the streaming resistance present at the time of exhausting the space between the insulator board and the probe substrate is relaxed, and evacuation can be evenly performed, so that the probe substrate and the substrate under test can be evenly adsorbed.
The second seal member preferably includes a substrate side ring-shaped electrode formed along the outer periphery of the probe substrate, and a board side ring-shaped electrode formed in the insulator board and in contact with the substrate side ring-shaped electrode.
Thus, sealing may be achieved with both ring-shaped electrodes, and a member only for sealing does not have to be provided at the probe substrate or the insulator board.
The probe substrate preferably has a substrate side electrode in electrical contact with the probe electrode, and the insulator board has a board side electrode in contact with the substrate side electrode.
Thus, the cable of the test device is electrically connected with a plurality of probe electrodes provided at the probe substrate through the board side electrode and the substrate side electrode, plurality of such substrate side electrodes are radially provided along the outer periphery of the probe substrate, and a plurality of such board side electrodes are radially provided along the outer periphery of the insulator board.
Thus, if the probe substrate and insulator board thermally expand as the temperature rises in testing, they expand radially, so the relative positional shift among the electrodes can be absorbed, and a sure contact state can be maintained.
As the substrate side electrodes, electrodes formed continuously from one surface of the probe substrate via the periphery to the other surface are preferable. The substrate-side electrode is electrically connected to a cable coated with an insulator, and the cable coated with the insulator is preferably electrically connected with the electrode through the through hole formed at the outer periphery of the probe substrate.
A tapered surface is provided at the outer periphery of the probe substrate on the side of the insulator board, the substrate side electrode is formed at the tapered surface, a wire is bonded to the substrate side electrode, and the wire is electrically connected to the electrode.
Thus, when the probe substrate and the insulator board are in contact, the wire-bonded part can be prevented from directly contacting the insulator board.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when-taken in conjunction with the accompanying drawings.